Aim to high temporal resolution of the streak image tube in streak camera, the factors which influence the physical temporal dispersion, technical temporal dispersion and time jitter of the sweep circuit were discussed. The streak image tube was optimized, in which a pair of traveling wave deflectors was located before a magnetic solenoid lens. The inner time-varying electric field of traveling wave deflectors was simulated by CST electromagnetic studio. And the propagation velocity of electromagnetic wave was calculated. The results show that when leg length is 8 mm, leg width is 1mm, interval is 0.24 mm, pin length is 2.5 mm, deflector thickness is 1 mm and deflector length is 17.12 mm, the moving velocity of electrons and propagation velocity of the electromagnetic wave are matching. Based on the electron trajectory tracing method and the Rayleigh criterion, dynamic temporal and spatial characteristics of the streak image tube were analyzed, a dynamic temporal resolution of 200 fs in single sweep mode, dynamic temporal resolution of 208 fs in synchronized sweep mode, and a dynamic spatial resolution of above 20 lp/mm were obtained.